how can i plot including sym data in graph?

i need help

i want to plot this equation in ficture

so , i make code

%%%%

fs=3000;
t= 0 : 1/fs : 10;

m_amplitude=1;
sensitivity=1;
fm=3;
fc=10;

frequency_deviation=m_amplitude*sensitivity;
modulation_index=frequency_deviation/fm

message=square(2*pi*fm*t);
syms t
F=int(message, [0 t]);

y=cos(2*pi*fc+modulation_index*F);

plot(t,y)

but it doesn't work

how can i plot including sym data in graph?

[Askic V]

Please look at the documentation:

https://www.mathworks.com/help/symbolic/fplot.html

Answer 1

[Star Strider]

Thia approach works —

fs=3000;
t= 0 : 1/fs : 10;

t = 0: 1/fs : 2.5;                                      % Substitute To Allow Evaluation Within 55 Seconds

m_amplitude=1;
sensitivity=1;
fm=3;
fc=10;

frequency_deviation=m_amplitude*sensitivity;
modulation_index=frequency_deviation/fm;

message = @(t) square(2*pi*fm*t);
% syms t
F= arrayfun(@(t)integral(message, 0, t), t);

Warning: Minimum step size reached near x = 2. There may be a singularity, or the tolerances may be too tight for this problem.

Warning: Minimum step size reached near x = 2. There may be a singularity, or the tolerances may be too tight for this problem.

y=cos(2*pi*fc+modulation_index*F);

plot(t,y)

However it takes too long to evaluate here, so I created a shortened version of the ‘t’ vector so it could be evaluated in the required 55 seconds. See the documentation on arrayfun for details.

An alternative (that I did not experiment with) could be to evaluate ‘message’ and use the cumtrapz function.

.

[규호]

thank you

[Star Strider]

As always, my pleasure!